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c029a6a49e
temporary tables of other sessions; that is unsafe because of the way our buffer management works. Per report from Stuart Bishop. This is redundant with the bufmgr.c checks in HEAD, but not at all redundant in the back branches.
503 lines
13 KiB
C
503 lines
13 KiB
C
/*
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* $PostgreSQL: pgsql/contrib/pageinspect/btreefuncs.c,v 1.9 2009/03/31 22:54:31 tgl Exp $
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*
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*
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* btreefuncs.c
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*
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* Copyright (c) 2006 Satoshi Nagayasu <nagayasus@nttdata.co.jp>
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*
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* Permission to use, copy, modify, and distribute this software and
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* its documentation for any purpose, without fee, and without a
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* written agreement is hereby granted, provided that the above
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* copyright notice and this paragraph and the following two
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* paragraphs appear in all copies.
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*
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE TO ANY PARTY FOR DIRECT,
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* INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING
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* LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
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* DOCUMENTATION, EVEN IF THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* THE AUTHOR SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS
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* IS" BASIS, AND THE AUTHOR HAS NO OBLIGATIONS TO PROVIDE MAINTENANCE,
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* SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
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*/
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#include "postgres.h"
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#include "access/heapam.h"
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#include "access/nbtree.h"
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#include "catalog/namespace.h"
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#include "catalog/pg_type.h"
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#include "funcapi.h"
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#include "miscadmin.h"
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#include "storage/bufmgr.h"
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#include "utils/builtins.h"
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extern Datum bt_metap(PG_FUNCTION_ARGS);
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extern Datum bt_page_items(PG_FUNCTION_ARGS);
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extern Datum bt_page_stats(PG_FUNCTION_ARGS);
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PG_FUNCTION_INFO_V1(bt_metap);
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PG_FUNCTION_INFO_V1(bt_page_items);
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PG_FUNCTION_INFO_V1(bt_page_stats);
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#define IS_INDEX(r) ((r)->rd_rel->relkind == RELKIND_INDEX)
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#define IS_BTREE(r) ((r)->rd_rel->relam == BTREE_AM_OID)
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#define CHECK_PAGE_OFFSET_RANGE(pg, offnum) { \
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if ( !(FirstOffsetNumber <= (offnum) && \
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(offnum) <= PageGetMaxOffsetNumber(pg)) ) \
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elog(ERROR, "page offset number out of range"); }
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/* note: BlockNumber is unsigned, hence can't be negative */
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#define CHECK_RELATION_BLOCK_RANGE(rel, blkno) { \
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if ( RelationGetNumberOfBlocks(rel) <= (BlockNumber) (blkno) ) \
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elog(ERROR, "block number out of range"); }
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/* ------------------------------------------------
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* structure for single btree page statistics
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* ------------------------------------------------
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*/
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typedef struct BTPageStat
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{
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uint32 blkno;
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uint32 live_items;
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uint32 dead_items;
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uint32 page_size;
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uint32 max_avail;
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uint32 free_size;
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uint32 avg_item_size;
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char type;
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/* opaque data */
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BlockNumber btpo_prev;
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BlockNumber btpo_next;
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union
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{
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uint32 level;
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TransactionId xact;
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} btpo;
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uint16 btpo_flags;
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BTCycleId btpo_cycleid;
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} BTPageStat;
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/* -------------------------------------------------
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* GetBTPageStatistics()
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*
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* Collect statistics of single b-tree page
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* -------------------------------------------------
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*/
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static void
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GetBTPageStatistics(BlockNumber blkno, Buffer buffer, BTPageStat * stat)
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{
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Page page = BufferGetPage(buffer);
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PageHeader phdr = (PageHeader) page;
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OffsetNumber maxoff = PageGetMaxOffsetNumber(page);
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BTPageOpaque opaque = (BTPageOpaque) PageGetSpecialPointer(page);
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int item_size = 0;
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int off;
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stat->blkno = blkno;
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stat->max_avail = BLCKSZ - (BLCKSZ - phdr->pd_special + SizeOfPageHeaderData);
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stat->dead_items = stat->live_items = 0;
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stat->page_size = PageGetPageSize(page);
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/* page type (flags) */
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if (P_ISDELETED(opaque))
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{
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stat->type = 'd';
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stat->btpo.xact = opaque->btpo.xact;
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return;
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}
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else if (P_IGNORE(opaque))
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stat->type = 'e';
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else if (P_ISLEAF(opaque))
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stat->type = 'l';
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else if (P_ISROOT(opaque))
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stat->type = 'r';
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else
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stat->type = 'i';
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/* btpage opaque data */
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stat->btpo_prev = opaque->btpo_prev;
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stat->btpo_next = opaque->btpo_next;
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stat->btpo.level = opaque->btpo.level;
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stat->btpo_flags = opaque->btpo_flags;
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stat->btpo_cycleid = opaque->btpo_cycleid;
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/* count live and dead tuples, and free space */
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for (off = FirstOffsetNumber; off <= maxoff; off++)
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{
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IndexTuple itup;
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ItemId id = PageGetItemId(page, off);
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itup = (IndexTuple) PageGetItem(page, id);
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item_size += IndexTupleSize(itup);
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if (!ItemIdIsDead(id))
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stat->live_items++;
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else
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stat->dead_items++;
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}
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stat->free_size = PageGetFreeSpace(page);
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if ((stat->live_items + stat->dead_items) > 0)
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stat->avg_item_size = item_size / (stat->live_items + stat->dead_items);
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else
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stat->avg_item_size = 0;
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}
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/* -----------------------------------------------
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* bt_page()
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*
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* Usage: SELECT * FROM bt_page('t1_pkey', 1);
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* -----------------------------------------------
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*/
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Datum
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bt_page_stats(PG_FUNCTION_ARGS)
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{
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text *relname = PG_GETARG_TEXT_P(0);
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uint32 blkno = PG_GETARG_UINT32(1);
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Buffer buffer;
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Relation rel;
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RangeVar *relrv;
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Datum result;
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HeapTuple tuple;
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TupleDesc tupleDesc;
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int j;
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char *values[11];
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BTPageStat stat;
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if (!superuser())
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ereport(ERROR,
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(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
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(errmsg("must be superuser to use pageinspect functions"))));
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relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
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rel = relation_openrv(relrv, AccessShareLock);
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if (!IS_INDEX(rel) || !IS_BTREE(rel))
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elog(ERROR, "relation \"%s\" is not a btree index",
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RelationGetRelationName(rel));
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/*
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* Reject attempts to read non-local temporary relations; we would
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* be likely to get wrong data since we have no visibility into the
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* owning session's local buffers.
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*/
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if (RELATION_IS_OTHER_TEMP(rel))
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ereport(ERROR,
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(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
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errmsg("cannot access temporary tables of other sessions")));
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if (blkno == 0)
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elog(ERROR, "block 0 is a meta page");
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CHECK_RELATION_BLOCK_RANGE(rel, blkno);
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buffer = ReadBuffer(rel, blkno);
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/* keep compiler quiet */
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stat.btpo_prev = stat.btpo_next = InvalidBlockNumber;
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stat.btpo_flags = stat.free_size = stat.avg_item_size = 0;
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GetBTPageStatistics(blkno, buffer, &stat);
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/* Build a tuple descriptor for our result type */
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if (get_call_result_type(fcinfo, NULL, &tupleDesc) != TYPEFUNC_COMPOSITE)
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elog(ERROR, "return type must be a row type");
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j = 0;
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%d", stat.blkno);
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%c", stat.type);
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%d", stat.live_items);
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%d", stat.dead_items);
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%d", stat.avg_item_size);
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%d", stat.page_size);
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%d", stat.free_size);
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%d", stat.btpo_prev);
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%d", stat.btpo_next);
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values[j] = palloc(32);
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if (stat.type == 'd')
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snprintf(values[j++], 32, "%d", stat.btpo.xact);
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else
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snprintf(values[j++], 32, "%d", stat.btpo.level);
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%d", stat.btpo_flags);
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tuple = BuildTupleFromCStrings(TupleDescGetAttInMetadata(tupleDesc),
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values);
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result = HeapTupleGetDatum(tuple);
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ReleaseBuffer(buffer);
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relation_close(rel, AccessShareLock);
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PG_RETURN_DATUM(result);
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}
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/*-------------------------------------------------------
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* bt_page_items()
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*
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* Get IndexTupleData set in a btree page
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*
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* Usage: SELECT * FROM bt_page_items('t1_pkey', 1);
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*-------------------------------------------------------
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*/
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/*
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* cross-call data structure for SRF
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*/
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struct user_args
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{
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Page page;
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OffsetNumber offset;
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};
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Datum
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bt_page_items(PG_FUNCTION_ARGS)
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{
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text *relname = PG_GETARG_TEXT_P(0);
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uint32 blkno = PG_GETARG_UINT32(1);
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Datum result;
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char *values[6];
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HeapTuple tuple;
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FuncCallContext *fctx;
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MemoryContext mctx;
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struct user_args *uargs;
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if (!superuser())
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ereport(ERROR,
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(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
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(errmsg("must be superuser to use pageinspect functions"))));
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if (SRF_IS_FIRSTCALL())
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{
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RangeVar *relrv;
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Relation rel;
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Buffer buffer;
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BTPageOpaque opaque;
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TupleDesc tupleDesc;
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fctx = SRF_FIRSTCALL_INIT();
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relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
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rel = relation_openrv(relrv, AccessShareLock);
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if (!IS_INDEX(rel) || !IS_BTREE(rel))
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elog(ERROR, "relation \"%s\" is not a btree index",
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RelationGetRelationName(rel));
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/*
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* Reject attempts to read non-local temporary relations; we would
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* be likely to get wrong data since we have no visibility into the
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* owning session's local buffers.
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*/
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if (RELATION_IS_OTHER_TEMP(rel))
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ereport(ERROR,
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(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
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errmsg("cannot access temporary tables of other sessions")));
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if (blkno == 0)
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elog(ERROR, "block 0 is a meta page");
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CHECK_RELATION_BLOCK_RANGE(rel, blkno);
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buffer = ReadBuffer(rel, blkno);
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/*
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* We copy the page into local storage to avoid holding pin on the
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* buffer longer than we must, and possibly failing to release it at
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* all if the calling query doesn't fetch all rows.
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*/
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mctx = MemoryContextSwitchTo(fctx->multi_call_memory_ctx);
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uargs = palloc(sizeof(struct user_args));
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uargs->page = palloc(BLCKSZ);
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memcpy(uargs->page, BufferGetPage(buffer), BLCKSZ);
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ReleaseBuffer(buffer);
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relation_close(rel, AccessShareLock);
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uargs->offset = FirstOffsetNumber;
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opaque = (BTPageOpaque) PageGetSpecialPointer(uargs->page);
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if (P_ISDELETED(opaque))
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elog(NOTICE, "page is deleted");
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fctx->max_calls = PageGetMaxOffsetNumber(uargs->page);
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/* Build a tuple descriptor for our result type */
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if (get_call_result_type(fcinfo, NULL, &tupleDesc) != TYPEFUNC_COMPOSITE)
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elog(ERROR, "return type must be a row type");
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fctx->attinmeta = TupleDescGetAttInMetadata(tupleDesc);
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fctx->user_fctx = uargs;
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MemoryContextSwitchTo(mctx);
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}
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fctx = SRF_PERCALL_SETUP();
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uargs = fctx->user_fctx;
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if (fctx->call_cntr < fctx->max_calls)
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{
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ItemId id;
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IndexTuple itup;
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int j;
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int off;
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int dlen;
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char *dump;
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char *ptr;
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id = PageGetItemId(uargs->page, uargs->offset);
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if (!ItemIdIsValid(id))
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elog(ERROR, "invalid ItemId");
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itup = (IndexTuple) PageGetItem(uargs->page, id);
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j = 0;
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%d", uargs->offset);
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values[j] = palloc(32);
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snprintf(values[j++], 32, "(%u,%u)",
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BlockIdGetBlockNumber(&(itup->t_tid.ip_blkid)),
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itup->t_tid.ip_posid);
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%d", (int) IndexTupleSize(itup));
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%c", IndexTupleHasNulls(itup) ? 't' : 'f');
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%c", IndexTupleHasVarwidths(itup) ? 't' : 'f');
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ptr = (char *) itup + IndexInfoFindDataOffset(itup->t_info);
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dlen = IndexTupleSize(itup) - IndexInfoFindDataOffset(itup->t_info);
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dump = palloc0(dlen * 3 + 1);
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values[j] = dump;
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for (off = 0; off < dlen; off++)
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{
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if (off > 0)
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*dump++ = ' ';
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sprintf(dump, "%02x", *(ptr + off) & 0xff);
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dump += 2;
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}
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tuple = BuildTupleFromCStrings(fctx->attinmeta, values);
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result = HeapTupleGetDatum(tuple);
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uargs->offset = uargs->offset + 1;
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SRF_RETURN_NEXT(fctx, result);
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}
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else
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{
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pfree(uargs->page);
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pfree(uargs);
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SRF_RETURN_DONE(fctx);
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}
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}
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/* ------------------------------------------------
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* bt_metap()
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*
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* Get a btree's meta-page information
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*
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* Usage: SELECT * FROM bt_metap('t1_pkey')
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* ------------------------------------------------
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*/
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Datum
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bt_metap(PG_FUNCTION_ARGS)
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{
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text *relname = PG_GETARG_TEXT_P(0);
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Datum result;
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Relation rel;
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RangeVar *relrv;
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BTMetaPageData *metad;
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TupleDesc tupleDesc;
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int j;
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char *values[6];
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Buffer buffer;
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Page page;
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HeapTuple tuple;
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if (!superuser())
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ereport(ERROR,
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(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
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(errmsg("must be superuser to use pageinspect functions"))));
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relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
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rel = relation_openrv(relrv, AccessShareLock);
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if (!IS_INDEX(rel) || !IS_BTREE(rel))
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elog(ERROR, "relation \"%s\" is not a btree index",
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RelationGetRelationName(rel));
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/*
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* Reject attempts to read non-local temporary relations; we would
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* be likely to get wrong data since we have no visibility into the
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* owning session's local buffers.
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*/
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if (RELATION_IS_OTHER_TEMP(rel))
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ereport(ERROR,
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(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
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errmsg("cannot access temporary tables of other sessions")));
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buffer = ReadBuffer(rel, 0);
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page = BufferGetPage(buffer);
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metad = BTPageGetMeta(page);
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/* Build a tuple descriptor for our result type */
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if (get_call_result_type(fcinfo, NULL, &tupleDesc) != TYPEFUNC_COMPOSITE)
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elog(ERROR, "return type must be a row type");
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j = 0;
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%d", metad->btm_magic);
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%d", metad->btm_version);
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%d", metad->btm_root);
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%d", metad->btm_level);
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%d", metad->btm_fastroot);
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values[j] = palloc(32);
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snprintf(values[j++], 32, "%d", metad->btm_fastlevel);
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tuple = BuildTupleFromCStrings(TupleDescGetAttInMetadata(tupleDesc),
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values);
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result = HeapTupleGetDatum(tuple);
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ReleaseBuffer(buffer);
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relation_close(rel, AccessShareLock);
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PG_RETURN_DATUM(result);
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}
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